It's literally the most nationalistic, xenophobic economic policy that we have ever had the misfortune of experiencing. It is the ultimate punishment for consumers (i.e. all Americans, but especially those who can't afford to buy things at higher prices - i.e. the working people and the poor whom liberals/progressives/the Left say they care about) and the ultimate godsend for American capitalists. Furthermore, it literally cuts the United States off from the global economy which we all benefit from to one extent or the other.
Pretty much nothing you posted is true. If you have wage, safety, and environmental standards your costs of production can be higher. It does you no good to then allow importation of cheap hazardous goods from countries with no standards. The goods may cost more with some trade barriers in place but you will also be able to keep your workers' wages up.
I think what people on the left want is certain minimal standards everywhere. They want better wages for workers in third world countries. What they don't want is a global race to the bottom. If anyone has seen the old textile towns of New England and compares them to the slums in Bangladesh where clothes are now made they will understand why there is such an outcry about globalization.
